I have been affirmatively opposed to organized religion since about the age of 14. But I love Christmas. It's magical. As you can imagine, this is often a point of contention in debates: "Christmas wouldn't be here if it weren't for Christ, so how can you say 'religion poisons everything'?" they ask me.
if you want to "keep Christ in Christmas," by all means, set up your Nativity scene and go to midnight Mass on Christmas Eve. It's a free country. I, along with the increasing number of non-Christians, will be by the fire, glass of wine in-hand, listening to some Nat King Cole.